Add certificate config and docs

backend/right_tree/settings.py

@@ -88,7 +88,7 @@ DATABASES = {
         'NAME': os.getenv("RIGHTTREE_DB", "postgres"),
         'USER': os.getenv("RIGHTTREE_DB_USER", "postgres"),
         'PASSWORD': os.getenv("RIGHTTREE_DB_PASSWORD", "postgres"),
-        'HOST': os.getenv("POSTGRES_DB", "postgres"),
+        'HOST': "postgres",
         'PORT': 5432,
     }
 }